Conduction in ulnar nerve bundles that innervate the proximal and distal muscles: a clinical trial

<p>Abstract</p> <p>Background</p> <p>This study aims to investigate and compare the conduction parameters of nerve bundles in the ulnar nerve that innervates the forearm muscles and hand muscles; routine electromyography study merely evaluates the nerve segment of distal (hand) muscles.</p> <p>Methods</p> <p>An electrophysiological evaluation, consisting of velocities, amplitudes, and durations of ulnar nerve bundles to 2 forearm muscles and the hypothenar muscles was performed on the same humeral segment.</p> <p>Results</p> <p>The velocities and durations of the compound muscle action potential (CMAP) of the ulnar nerve bundle to the proximal muscles were greater than to distal muscles, but the amplitudes were smaller.</p> <p>Conclusions</p> <p>Bundles in the ulnar nerve of proximal muscles have larger neuronal bodies and thicker nerve fibers than those in the same nerve in distal muscles, and their conduction velocities are higher. The CMAPs of proximal muscles also have smaller amplitudes and greater durations. These findings can be attributed to the desynchronization that is caused by a wider range of distribution in nerve fiber diameters.</p> <p>Conduction parameters of nerve fibers with different diameters in the same peripheral nerve can be estimated.</p

MHC Class I Function at the Neuronal Synapse

The major histocompatibility complex class I (MHC class I) encodes a family of immune recognition molecules acting as ligands at immune synapses, thereby conveying adaptive and innate immunity. MHC class I proteins are expressed by all nucleated vertebrate cells, including neurons, and can mediate immune clearance of neurotropic viruses in the CNS. Intriguingly, there are now indications for a non-immune role of MHC class I signalling at neuronal synapses. Thus, neuronal MHC class I expression has been linked to synaptic plasticity and the modulation of neuronal functions. Up to this day, two MHC class I receptors have been identified at the neuronal synapse, which provide a molecular basis for MHC class I-dependent signalling across the synapse. Possible clinical implications of MHC class I expression in the CNS are currently being investigated in relation to neurodevelopmental and neurodegenerative diseases, in which synaptic dysfunction is a cardinal feature